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AKwUvBz6e/GMBlxF1cnpsapWGu89ZDeL3qe70lzE4Dwe/Wzlj0KkXXln9I5jmRGQe3fwqwlmG62mBfyJu/gyEw==@vger.kernel.org X-Gm-Message-State: AFq9FYImat8V9UBbaLjoPwjiYjKgcjJKtC8vxzPPX8N0WLgLt0EBIahH qfWeesM/GUbzgjYKap4xWtbpLUC65PqOZCq+BEWTm+rXP1zzv+Bwz458N4Zmiz+uLS9xsegmXKH snUh2KO8O5c2zdXK3picAINiG8JO0OOeVWsqSnFlXZ/KEHdlgRScQPTiIDtE= Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:10c7:b0:4f1:5068:b95a with SMTP id 5614622812f47-50c4ed40b02mr19529086b6e.23.1792094903787; Thu, 15 Oct 2026 13:08:23 -0700 (PDT) Date: Thu, 15 Oct 2026 13:08:23 -0700 In-Reply-To: <6a14aff8.050a0220.2385e8.0019.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6ad132b7.7952420f.283480.00dc.GAE@google.com> Subject: Re: [syzbot] [raid?] [block?] possible deadlock in blk_request_module (2) From: syzbot To: axboe@kernel.dk, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, song@kernel.org, syzkaller-bugs@googlegroups.com, yukuai@fnnas.com Content-Type: text/plain; charset="UTF-8" syzbot has found a reproducer for the following issue on: HEAD commit: b810335a0699 Add linux-next specific files for 20261015 git tree: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git console output: https://syzkaller.appspot.com/x/log.txt?x=1605ffd1580000 kernel config: https://syzkaller.appspot.com/x/.config?x=1b8bbfb3c8b8bab9 dashboard link: https://syzkaller.appspot.com/bug?extid=fb0ff9bfe34ad282ebd4 compiler: Debian clang version 22.1.8 (1~deb13u4), Debian LLD 22.1.8 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1505ffd1580000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+fb0ff9bfe34ad282ebd4@syzkaller.appspotmail.com md/raid1:md125: active with 1 out of 1 mirrors md125: detected capacity change from 0 to 8192 ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz-executor123/5954 is trying to acquire lock: ffffffff90960c40 (major_names_lock){+.+.}-{4:4}, at: blk_probe_dev block/genhd.c:885 [inline] ffffffff90960c40 (major_names_lock){+.+.}-{4:4}, at: blk_request_module+0x35/0x2a0 block/genhd.c:901 but task is already holding lock: ffff8880236d8358 (&mddev->reconfig_mutex){+.+.}-{4:4}, at: mddev_lock drivers/md/md.h:713 [inline] ffff8880236d8358 (&mddev->reconfig_mutex){+.+.}-{4:4}, at: mddev_suspend_and_lock+0x48/0xf0 drivers/md/md.h:1019 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&mddev->reconfig_mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x197/0x15a0 kernel/locking/mutex.c:821 mddev_lock_nointr drivers/md/md.h:734 [inline] md_start_sync+0x179/0x1010 drivers/md/md.c:10275 process_one_work kernel/workqueue.c:3495 [inline] process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659 kthread+0x38b/0x480 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #2 ((work_completion)(&mddev->sync_work)){+.+.}-{0:0}: process_one_work kernel/workqueue.c:3471 [inline] process_scheduled_works+0xc03/0x1630 kernel/workqueue.c:3578 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659 kthread+0x38b/0x480 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #1 ((wq_completion)md_misc){+.+.}-{0:0}: touch_wq_lockdep_map+0xcb/0x180 kernel/workqueue.c:4272 __flush_workqueue+0x148/0x10b0 kernel/workqueue.c:4314 md_alloc+0x32/0xf20 drivers/md/md.c:6334 md_alloc_and_put+0x1a/0x1f0 drivers/md/md.c:6423 blk_probe_dev block/genhd.c:888 [inline] blk_request_module+0x27d/0x2a0 block/genhd.c:-1 blkdev_get_no_open+0x3f/0xe0 block/bdev.c:870 blkdev_open+0x1d7/0x600 block/fops.c:677 do_dentry_open+0x80e/0x1360 fs/open.c:1000 vfs_open_consume+0x4a/0x350 fs/open.c:1131 do_open fs/namei.c:4892 [inline] path_openat+0x16fc/0x20f0 fs/namei.c:5057 do_file_open+0x23e/0x4a0 fs/namei.c:5086 do_sys_openat2+0x115/0x200 fs/open.c:1442 do_sys_open fs/open.c:1448 [inline] __do_sys_openat fs/open.c:1788 [inline] __se_sys_openat fs/open.c:1783 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1783 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (major_names_lock){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3209 [inline] check_prevs_add kernel/locking/lockdep.c:3328 [inline] validate_chain kernel/locking/lockdep.c:3952 [inline] __lock_acquire+0x164c/0x2de0 kernel/locking/lockdep.c:5288 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x197/0x15a0 kernel/locking/mutex.c:821 blk_probe_dev block/genhd.c:885 [inline] blk_request_module+0x35/0x2a0 block/genhd.c:901 blkdev_get_no_open+0x3f/0xe0 block/bdev.c:870 bdev_file_open_by_dev+0xa0/0x240 block/bdev.c:1091 md_import_device+0x2e9/0x650 drivers/md/md.c:3847 md_add_new_disk+0x669/0x1850 drivers/md/md.c:7549 md_ioctl+0x2005/0x2610 drivers/md/md.c:8499 blkdev_ioctl+0x5e3/0x740 block/ioctl.c:798 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: major_names_lock --> (work_completion)(&mddev->sync_work) --> &mddev->reconfig_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&mddev->reconfig_mutex); lock((work_completion)(&mddev->sync_work)); lock(&mddev->reconfig_mutex); lock(major_names_lock); *** DEADLOCK *** locks held by syz-executor123/5954: 1, last CPU#0: #0: ffff8880236d8358 (&mddev->reconfig_mutex){+.+.}-{4:4}, at: mddev_lock drivers/md/md.h:713 [inline] #0: ffff8880236d8358 (&mddev->reconfig_mutex){+.+.}-{4:4}, at: mddev_suspend_and_lock+0x48/0xf0 drivers/md/md.h:1019 stack backtrace: CPU: 0 UID: 0 PID: 5954 Comm: syz-executor123 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2087 check_noncircular+0x12f/0x150 kernel/locking/lockdep.c:2219 check_prev_add kernel/locking/lockdep.c:3209 [inline] check_prevs_add kernel/locking/lockdep.c:3328 [inline] validate_chain kernel/locking/lockdep.c:3952 [inline] __lock_acquire+0x164c/0x2de0 kernel/locking/lockdep.c:5288 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x197/0x15a0 kernel/locking/mutex.c:821 blk_probe_dev block/genhd.c:885 [inline] blk_request_module+0x35/0x2a0 block/genhd.c:901 blkdev_get_no_open+0x3f/0xe0 block/bdev.c:870 bdev_file_open_by_dev+0xa0/0x240 block/bdev.c:1091 md_import_device+0x2e9/0x650 drivers/md/md.c:3847 md_add_new_disk+0x669/0x1850 drivers/md/md.c:7549 md_ioctl+0x2005/0x2610 drivers/md/md.c:8499 blkdev_ioctl+0x5e3/0x740 block/ioctl.c:798 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4e137daefb Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1c 48 8b 44 24 18 64 48 2b 04 25 28 00 00 RSP: 002b:00007ffea3973750 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f4e137daefb RDX: 00007ffea39737d0 RSI: 0000000040140921 RDI: 0000000000000005 RBP: 0000000000000005 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000007 R13: 00007ffea3973830 R14: 00007f4e1385fcc0 R15: 0000000000000002 md: could not open device unknown-block(0,0). md: md_import_device returned -6 --- If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing.